Cam-path-generating machine.



EHWVARD E. FOSTER, OF BEVERLY, MASSACHUSETTS.

CAM-PATH-GENERATING' MACHINE.

Specification of Letters Patent.

Patented lUlee. 4t, limit.

Application led Uetober/t, 1913. Serial No. 797,082.

l ating Machine, of which the following is a specilieation.

As Awell known to those skilled in the 'art it is'customary in the manufacture of cams tofirst generate the cam path upon paper and then scratch the outline of the generated cam path upon a leader. The leader is then cut down to the inner working surface of the path afterwhich it 'is inserted into a cam cutting machine where it directs the operation of the cutting tool. Sometimes the cam path is generated upon wood which is used as a pattern to guide a tool in cutting the leader down to the inner working surface of the cam path. As there are three principal kindsof motion imparted to a follower by a cam, namely, harmonic, uniform and gravity motions, to generate a cam path so that it will impart the proper motion t0 a follower' including the proper sequence of rises, drops and dwells requires considerable knowledge, experience and skill upon the part of the designer. l have discovered that some of the well known mechanical devices are adapted to impart motions correspondv ing to the harmonie, uniform` and gravity motions of a cam follower. For instance, a crank in rotating through 180 degrees imparts a harmonic motion to a driven member, a swinging pendulum has a gravity motion and an inclined plane imparts to a follower equal rises in equal intervals of time, or uniform motion. Therefore, l have conceived the idea of utilizing mechanism other than a pattern in cutting the leader down to the inner working surface of a cam-path.

rlthe object of the present invention is to produce a machine for cutting a leader down to the inner working surface of a cam path in such manner as to obviate the necessity of a preliminary generation of the cam path. To the accomplishment of this object and vsuch others as may hereinafter appear the features of the invention relate to certain devices, combinations and arrangement of parts hereinafter described and then set forth broadly and in detail in theappended` claims which possess advantageswhich will be apparent to those skilled in the a.t.

The various features-of the presentinvention will be best understood from an inspection of the accompanying drawing illustrating one embodiment of the invention, in which,

Figure l is a perspective, partly in section, of a machinefor-cutting a leader down to he inner working surface of a cam `path; an

Fig. 2 is a longitudinal sectional elevation of the crank for shifting the' path of travel of the cutter.

In the illustrated embodiment; of the'invention the leader is cut down to the inner working surface of the cam path by a rotary cutter. The leader isrotated to trans-l lfer the point of operation-of the cutter around the leader and thecutter is shifted toward and from the axis of rotation of erated. ln order to adapt the machine to generate any desired cam path adjustments are provided for varying the operation of the cutter in accordance withvariations in the. base circles, rises, drops dwells and times in the different forms of cams to be designed. The leader l is clamped to the upper face of a rotatable disk 2 by a nut 3 and washer 4 and is held from rotation on the disk by a pair of pins 5 projecting from the/disk and arranged to engage a pair of holes formed in the leader. The peripheral edge of the disk 2 is provided with'an index 6 which coperates with a pointer 7 carried by the machine frame to serve asl a guide for the operative in determining the lengthof one of the rotative steps of the disk. The disk 2 is held clamped between the rotative steps by a plate 8 slidably mounted in a block 9 formed on the machine frame.` The plate 8 is held in clamping position by a clamp'lO arranged tobind. the plate to the block 9. 4

ln order to simultaneously generate a cam path and cutthe leader down to the inner working` surface of the cam path the machineis provided with a cutter 11 the shank of which is carried' in the hollow taperedend of' a shaft 12 rotatably mounted in a tool carrying frame 13. The slaft l2 carries a sheave 14 which is driven through a belt (not shown) from` some suitable source of power. In orderto elevate and depress the cutter the shaft 12 carries a sleeve 14;a which is engaged by al screw 15 held from longitudinal movement in a lug 16 formed on the .trame 13. The upper end of the screw is provided with a knurled head 17 manipulation of which permits the operative to elevate or. depress the cutter. The frame 13 is secured to a horizontal rod 18, mounted to reciprocate in the frame of the machine, by a clamping bolt 19.

`With the construction so far described a rotation of the leader will transfer the. point of operation of the cutter around the leader. In order to shift the point of operation of the cutter so as to change the direction orn its path the rod 18 is connected to a yoke 20 mounted to slide upon guides 2l carried by the frame of the machine. The yoke 2O embraces a rectangular block 22 which is swiveled upon a crank pin 23 slidably mounted in a slot 24 formed on a platform 25. The platform 25 is formed on the upper face of a disk 26 rotatably mounted on the machine frame. The crankpin 23 is mounted on a block 27 which slides in ways 28 formed in the platform 25. lVith this construction the cutter is reciprocated toward and from the axis of the leader by a crank which is driven by the rotation of the disk 26. As it is desirable to vary the throw of the crank the upper face of the platform 25 is provided with an index 29 to serve asa guide for the operative in adjusting the yoke 20 and' its associated parts nearer to or farther from the axis of the disk 26. To guide the cutter 11 to reciprocate radially of the leader .l the frame of the machine carries a horizontal rod 30 arranged in a vertical' plane intersecting the axis or' the leader. The rod 30 loosely passes through the frame 1'3 so that the tool may reciprocate freely thereon and thus be constrained to move radially toward and from the axis of the leader. rlhe peripheral edge o the upper face of the disk 26 is provided with an index 31 which coperates with the pointer 32 carried by the frame of the machine to serve as a guide for the operative in determining the length of the reciprocating steps imparted to the cutter. The disk 26 is held clamped between the reciprocatin steps of the cutter by a plate 33 slidably mounted in a block 3d formed on the frame of the machine. The plate 33 is held in clamping position by a clamp arranged to bind the plate 33 to the block 34.

In using the machine to cut a leader down to the inner working surface of a cam path intended to impart, for instance, a harmonic rise of four inches in degrees, a harmonic drop of four inches in the next Li5 degrees, and a dwell during the remaining angle t' the frame 13 is adjusted upon the rod 30 so that the distance from the center of the shaftv 12 to the axis of the leader 1 corresponds to the base circle of the cani path to be generated which, as well known to those skilled in the art, is a circle having its center at the 'center or' the cani path and a radius equal to the shortestdistance to the theoretical cam groove. rlhe rod 30 is provided with an index 411 to Serve as a guide for the. operative in .adjustingthe cutter for the base circle. After this adjustment is made the frame 13 is temporarily held by av screw 4:2 which clamps the frame 13 to the rod 30. The bolt 19 is then loosened to free the rod 18,(and the yoke 2O is then adjusted along the platform until the axis of the crank pin 23 is two inches from the axis of rotation of the disk 26. This adjustment is made when the platform 25 is at its limit ,of movem. :1 one dire/.x1 tion. After this adjustment is made the frame 13 is unclamped from the rod 30 and again clamped to the rod 18.

Now it being desired to generate a cani path for imparting to a cam follower a harmonic rise of four inches in 90 degrees and to cut the leader down to the 'inner working surface of the camypath the cutter is ron tated and fed lonnwardly by the operative until a hole is-vcut throughlhe leader. Fxperience has demonstrated that it requires thirty cuts to form a. ninety degree cani cui' in the leader. Consequently after the iirst cut is formed in the leader the cutie-.r is olevated above the leader and the disk carry ing the leader is rotated three degrees and" then clamped. is it 1s necessary to rotate the crank pin 23 through one hundred and eighty degrees While the leader l rotated through ninety degrees in order to obiain .-i. harmonic rise of :four inches in ninety da grecs the disk 2G is nonrelated one-lhirricth of one hundred and eighty degrees or sin degrees. Then the cutter is led downwardly to again cut through the leader. rlhe cutter 11, disk 2 and ldisk 26 are successively operated in the inzuiner described until the disks 2 and 26 are rotated through ninety and one hundred and eighty degrees respectively. rlhe leader is then providml with a cani path which will impart to a cani follower a harmonic rise of four inches in ninety degrees. 'llo obtain a harmonic drop of four inches in forty-live degrees the disks 2 and 2G are rotated three degrees and twelve degrees at a time respectively after the for-- mation or' a cut by the cutter. To obtain a dwell during the remaining angle or' two hundred and twenty-five degrees the disk 26 is firmly clamped while the disk 2 and the cutter 11 are operated in the manner hereinbefore referred to.

lll/*hilo the machine has been described as generating a specific cam path it will. he readily apparent to those skilled in the art that the machiifeis adapted to generate any cam path for imparting to a reciprocating cam follower any combination of harmonic motions and dwells as the machine is pro vided with the necessary adjustments for varying the operation of the tool upon the leader in accordance with the variations in the base circles, rises, drops and times of the cam paths which it may be desired to generate.

While the invention has'been illustrated and described in connection with a machine for generating a cam` path for imparting harmonic motion to a reciprocating follower it must be understood that this is merely one embodiment of the invention which may have a variety of forms depending uponthe kind of motion which it is desired to impart to a follower, the kind of cam to be provided with a cam path and whether the fol! lower is offset or mounted to oscillate or reciprocate.- Neither is the specific construction and arrangement of parts shown and described essential nor is the conjoint use of all the features of the invention I essential eXcept'so far as specied' in the appended claims and it may be varied or modified Without departing from the principal features of the inventlon.

What is claimed as new,- is:

l1. A machine for generating a cam path and cutting a leader down to the inner working surface of the cam path, having, in combination, a cutter vmovable to cut the-leader down to the inner working surface of the cam path, mechanism for relatively moving the leader and'cutter to transfer the point of operation of the cutter around the leader, and means for varying the said relative I movement to generate a continuous cam path having differential drops and substantially as described.

2. A machine for enerating a cam path and cutting a leader van to the inner workrises therein,

@epics of this .patent may be obtained for ve cents ing surface of the cam path, having,in cbmbination, a cutter movable to cut the leader down to the inner working surface of the cam path, mechanism for relatively moving the leader and cutter to transfer the point of operation of theeutter around the leader, and means for varying the said relative movement to generate a continuous harmonic motion cam path having differential drops and rises therein, substantially as described.

3. A machine for generating a cam path and cutting a leader down to the inner working surface of the cam path, having, in co1nbination, a cutter, a leader support rotatable to transfer the point of operation of the cutter around the leader, and mechanism other thanl a pattern for shifting the cutter toward and from the axis of the leader to change the direction of its path, substantially as described.

4. A machine for generating a cam path and cutting a leader down tothe inner working surface of the cam path, having, in combination, a cutter, a leader support rotatable to transfer the point of operation of the cutter around the leader, and a crank for shifting the cutter toward and from the axis of the leader to change the direction of its path, substantially asy described.

5. A machine for generating a cam path and cutting a leader down to the inner work ing surface of the cam path, having, in combination, a cutter, a leader support rotatable relative to the cutter,l mechanism for shifting the cutter toward and from the axis of the leader to change the direction of its path around the leader for varying the said rela tive movement of the leader and cutter to generate a continuous cam path having differential drops-and rises therein.

EDWARD E. FOSTER. Witnesses:

CHARLES E. Grauen, ELMER B. GrnUsH.

each, by addressinglthe commissioner of Patente,

Washington, I). C. 

